September 19, 2012

Antarctic Ice Facing Changes By Fast-Flowing Glaciers

A new study found that fast-flowing and narrow glaciers could trigger massive changes in the Antarctic ice sheet, inevitably adding sea-level rise and ice-sheet decay.

The team tested high-resolution model simulations against reconstructions of the Antarctic ice sheet from 20,000 years ago.

Writing in the journal Proceedings of the National Academy of Sciences (PNAS), they said they used a new model during their study, capable of resolving responses to ice-streams and other fine-scale dynamic features that interact over the entire ice sheet.

Their results showed that while glacier acceleration triggered by ocean warming is relatively localized, the extent of the resultant ice-sheet thinning is far more widespread.

These findings are particularly important in light of recently observed dynamic changes at the margins of Antarctica. They also highlighted areas that are more susceptible than others to changes in ocean temperatures.

“However, our results have confirmed recent observations suggesting that ocean warming can trigger increased flow of ice through these narrow corridors. This can cause inland sectors of the ice-sheet - some larger than the state of Victoria - to become thinner and flow faster."

The glaciers responding most rapidly to warming oceans were found in the Weddell Sea, the Admundsen Sea, the central Ross Sea and in the Amery Trough.

“To get a sense of the scale, the Antarctic ice sheet is 3km deep - three times the height of the Blue Mountains in many areas - and it extends across an area that is equivalent to the distance between Perth and Sydney," said Fogwill.

“Despite its potential impact, Antarctica's effect on future sea level was not fully included in the last IPCC report because there was insufficient information about the behavior of the ice sheet. This research changes that. This new, high-resolution modeling approach will be critical to improving future predictions of Antarctica's contribution to sea level over the coming century and beyond.”